We were sending to userspace unnecessary exit events, consuming
unnecessary CPU cycles.
We only intercept execve and execveat, but sched_process_exit is invoked
by more functions (sched_process_exit, clone, ...), so we were receiving
on the daemon events that we did nothing with them, apart from consuming
CPU cycles.
On some scenarios like on servers running saltstack (as salt-master),
this caused to consume more CPU than needed.
cherry picked from 15fcf67535
On 68c2c8ae1a we excluded failed execve*
calls from being delivered to userspace, in order to get the binary that
was executed and avoid errors/confusion.
But on aarch64, it seems that we fail to save the exec event to a map,
so the event is never delivered to userspace.
So for the time being, send the exec events as soon as they arrive on
aarch64, without checking if the call failed.
We track new processes execution by intercepting the enter and exit
of the functions, but sometimes the exit hook is not called, so the
corresponding entry was not being removed from the map.
In this situation the map becomes full and accepts no new entries.
Now the entry is deleted from the map once the process exits, if it
still exists in the map.
Make use of kernel macros to decide for what architectures we compile
the modules.
On armv7l the connections module was failing due to iptunnel_xmit, so
exclude it from being compiled.
One can export ARCH=arm, ARCH=i386 or ARCH=arm64 to compile the modules
for these architectures, instead of hacing to edit the source files.
- Get cmdline arguments from kernel along with the absolute path to the
binary.
If the cmdline has more than 20 arguments, or one of the arguments is
longer than 256 bytes, get it from ProcFS.
- Improved stopping ebpf monitor method.
Improved process detections by monitoring new processes execution.
It allow us to know the path of a process before a socket is opened.
Closes#617
Other improvements:
- If we fail to retrieve the path of a process, then we'll use the comm
name of the connection/process.
- Better kernel connections detection.
- If debugfs is not loaded, we'll try to mount it, to allow to use
eBPF monitor method.
Future work (help wanted):
- Extract command line arguments from the kernel (sys_execve, or mm
struct).
- Monitor other functions (execveat, clone*, fork, etc).
- Send these events to the server (GUI), and display all the commands
an application has executed.
